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Halloween is Over, But Why is The HVAC System Still Making Scary Noises?

November 19, 2019

When your HVAC system is making frightening noises, it's time to call the pros.

All the Halloween decorations are put away, all the leftover candy is gone, and all the jack-o-lanterns are replaced with regular pumpkins, but why does it seem like your HVAC system is still acting spooky heading into Thanksgiving? 

If you’re not sure what those horrifying sounds are that you keep hearing through the walls, Maryland’s HVAC service and repair professionals are here to tell you what kind of sounds to keep an ear on, so your home will continue to receive the ideal heating it needs for this time of year.

This time of year, properly working heating is essential for making it through the cold winter we have ahead of us. When you keep hearing unsettling noises coming from the HVAC system—especially if it’s an older one, homeowners might find themselves in a spooky situation well-after Halloween. Here is what homeowners should listen for, so you can take the steps to ensure your HVAC problem doesn’t become an HVAC fright-fest.


Screeching or squealing HVAC noises indicate that it’s either time to replace a belt, or there’s a problem with the blower’s motor system. If the belt snaps or the motor finally breaks, your system’s blower will stop working. Although belts aren’t a very expensive repair, it’s better to have them replaced before they snap. Also, check to see if your blower unit’s oil port is accessible—if it’s not sealed, adding some lubricant might be a quick fix for your blower’s screeching and squealing noises.


When you hear rattling coming from the HVAC system, it could mean more than one thing. If the rattling is coming from inside the home, it could be a problem with the furnace—if this is the problem, shut off your HVAC system, and call a professional. If the rattling is coming from outside, it could mean that the problem is just a minor clog caused by dirt, grass, or twigs. The easy-to-fix solution is to shut down the power to your HVAC system and remove the debris. If you notice any damage to the compressor, fan, or coils, get in touch with a professional here(hyperlink). A hissing noise might mean that air is escaping from your HVAC system—wasting air. If you hear the hissing noise coming from the walls, it means that your ducts are leaking--but find out for sure before hand that the hissing isn’t due to your HVAC system’s settings.


A simple humming noise is a good indicator that your HVAC system is running the way it should be. But if you hear banging and clanking, then that means something is wrong and needs to be addressed ASAP, even if it’s a small issue, like loose pipes or parts rubbing together. When loose parts are banging and clanking together, there could be a serious issue to address. If not addressed correctly and in time, these banging and clanking noises can cost a homeowner a lot of money in system damage. If you notice excessive banging and clanking, turn the system off and call your technician.

It’s almost Thanksgiving, time to make sure your HVAC system is out of it’s Halloween spirit for when the relatives come over. Because, when it comes to residential or commercial HVAC systems, MaxAir is the leading heating and air conditioning company in central Maryland, and we know how to make sure your system runs the way it should, all year round. This Fall, make sure your HVAC system is working at top performance and not bumping in the night—be sure to address any disturbing HVAC noises coming from your appliances. For more information about how we can service you, click here.

A furnace filter is a removable screen that is located between the air intake and furnace motor. The purpose of the filter is to stop airborne particles and dust from entering and producing damage to the furnace. Without a filter, the furnace can become clogged and work harder – over time, this could lead to a breakdown of the unit which is a costly – and preventable – expense.